Island



(No Model.)

H. 0. NICHOLS. GOVERNOR FOR STEAM ENGINES.

Patented Apr. 9, 1895.

mun 4 UNITED STATES PATENT OFFICE.

HENRY C. NICHOLS, OF HOP-KINTON, RHODE ISLAND.

GOVERNOR FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 537,223, dated April 9,18$ 5.

Application filed November 24, 1890 Serial No. 372,413. (No model.)

T0 on whom it may concern:

Be it known that I, HENRY O. NICHOLS, a citizen of the United States,and a resident of Hopkinton, county of Washington, and State of RhodeIsland, have invented certain new and useful Improvements in Governorsfor Steam-Engines, of which the following is a specification.

My invention relates td thatclass of engines in which the governors areapplied directly to the fly-WheeL'orother wheel secured to the main ordriving shaft, and regulates the movements of the engine by changing thethrow of the eccentric, whereby the cutoff of the steam either earlieror later in the stroke of the piston is effected as the exigencies ofthe engine may demand.

In steam or air engines in which a cylinder With ordinary ports, piston,valve, 850., IS employed, andalso a crank shaft upon which a governor iscarried that controls the speed of the engine by lengthening andshortening the throw of the valve, the steam is cutoff as early in thestroke as is possible, the point of cut-off depending upon the powerrequired. In nearly all engines of this class,

the eccentric proper is carried upon an arm which is pivoted upon somepart of a wheel or spider on the main shaft,-in such manner that whenthe center of the eccentric is in line with the center of the pivot andshaft the throw of the eccentric causes the valve to travel a distanceequal to the lap and lead,

and by swinging the eccentric out of this line its throw is increasedand the valve made to travel a greater distance and the point of cutoffmade later in the stroke. The changing of the eccentric in respect tothis line is accomplished by a governor which is also carried upon somepart or parts of the wheel or spider and necessarily revolves with it,and

' the centrifugal force of weights revolving with the wheel and normallycounterbalanced by a spring or springs is utilized in this form ofgovernor to accomplish this result. As the speed increases, thecentrifugal force of the weights increases correspondingly andoverbalances the spring. The weights are thereby allowed to move fartherfrom the center of 1'o-- tation, and, in so doing the position of theeccentric is shifted, the throw of the valve shortened, and the enginereduced to its former speed. As the spring and weights balance.

each other under such conditions, they have but little power to resistany force tending to disturb their equilibriu m, and unless the partswith which they are connectedare well balanced, a vibratory motion isimparted to them which is injurious to the engine and the governor.Moreover it is evident that in a governor so constructed, there is atendency of the eccentric to drop whenever the point upon which it ispivoted is not directly above or below the shaft, or, in the case of asliding eccentric, whenever its ways are not horizontal.

In slide valves and piston valves as ordinarily constructed, the areaexposed to the.

pressure .of the steam at the end connected to the valve stem is less bythe cross section of the valve stem than the area at the other, and thisinequality in the areas causes an unbalanced condition, the pressure onthe greater tending to force the valve stem outward, and when used in ahorizontal form of engines, this-force tends to swing the eccentric toone side when connected directly to it and the pivot on which theeccentric is hung is either above or below the shaft, thereby giving anunsteady or vibratory motion to the governor; and, when on a verticalengine, it adds to the weight of the eccentric, when the pivot is not indirect line with the valve stem, causing the vibration to be greatereven than in a horizontal engine.

The object of my invention is, to obviate these and other defects, andto produce means whereby greater efficiency in the operation of 'theengine is attained; and, to these ends, my

invention consists, first, in the peculiar combination with theeccentric,-and the valve stem, of a bell crank lever interposed betweenthem, and, second, in various details of construction and arrangementsof parts, all as will hereinafter more fully appear.

In the drawing which accompanies and forms part of this specification,and which shows a side elevation, partly in section, of such parts of ahorizontal steam engine as will serve to illustrate my invention, A indicates a valve which may be either a slide or a piston valve, for theadmission or cut-off of the steam or air of an engine; B, the valvestem; 0, the governor wheel, and D the shaft upon which the governorwheel-is mounted.

Pivoted to the governor wheel, as at a or elsewhere on said wheel, is anarm I), carrying at its free end, an eccentric, E, having an ovalorifice indicated by the dotted line e, through 5 which the main shaft Dpasses.

Surrounding the eccentric E is a strap F which is embraced by the lowerend of the arm II, the latter being pivoted at t' to the end of thebell-crank lever I which, in turn, is

hung upon a pin, i, supportedby a standard J of the engine frames, andat its other end connected to the valve rod B. By thus connecting thevalve A with the eccentric E, the weight of the eccentric and itssupporting arm, when in the position shown, is transmitted to the valvestem B in the longitudinal direction or the line of the latter, which isnot the case when a valve stem is connected to its eccentric through theusual eccentric 2o strap and guide or arm.

Pivoted to the wheel 0, by pivots (1 cl, are levers K K, which areconnected and drawn together by a spring, L, and carry weights M, bymeans of which the levers are thrown outward by centrifugal force whenthe wheel is rotated. The outer free ends of these levers K K areconnected by rods e e with arms ff, projecting outward from a shortshaft N having suitable bearings carried by the wheel.

On this shaft, N, is secured a small eccentric or cam, O, that Works ina slot, h, formed in the arm I). A box fitting the said eccentric andsliding in the slot his indicated at 0 in the drawing.

In the construction of the governor per se, I claim no novelty, havingchosen this form to illustrate my invention which, as before stated,consists in the method of and means for preventing the action of gravityin the eecentric and arm from causing vibrations in the governor orengine; and while the drawing illustrates some of the parts ofahorizontal engine, it will be obvious that my invention is as welladapted for vertical engines.

In the well known form of valve illustrated, it will be seen that, asshown in the figure, there will be an increase of pressure in the rearend of the valve over what is exerted on the front end a? thereof, owingto'the reduced area of the latter occasioned by the valve stem whichprojects therefrom. This increase of pressure, in engines wheremoderately high pressure is used, can be practically so proportioned asto exactly balance the weight of the unbal anced parts of the governoreccentric, and to approximately balance it under ordinary conditions;but with low pressure, while the force would act in the right directionto lift upon the eccentric, it might not be sufficient to balance it. Tomake up this deficiency, I may increase the area of the rear end of thisvalve, or at the end opposite to that from which the stem projects, forthe greater the pressure of steam used, the greater will be the excessof pressure tending to force the valve stem forward and the force ofgravity in the eccentrio and arm is a given quantity.

Having thus described my invention,what I claim as new, and desire tosecure by Letters Patent of the United States, is-- 1. In an engine, thecombination with a shifting eccentric, a valve and a valve stemtherefor, of a strap for encircling the eccentric having a verticallyarranged arm, and a bell-crank lever one end of which is connected tothe valve stem and the other end to the vertically arranged arm,substantially as described.

2. In an engine, the combination with the valve and a shifting eccentricand governor therefor, of a bell-crank lever having one end supportingthe weight of the eccentric and the other end connected to the valvestem, whereby an excess of pressure on the valvein onedirection willcounterbalance the weight of said eccentric, substantially as described.

3. The combination with ashifting eccentric governor of an engine, and areciprocating valve and stem therefor, of a bell-crank lever having oneend connected to said rod and having its otherend connected to a supportfor eccentric, the latter connection being in the vertical line of theaxis of the eccentric shaft, substantially as described.

4. The combination with a shifting eccentric governor of an engine, anda reciprocating valve and stem for said engine, of an arm extendingsubstantially vertically upward from the eccentric and; its strap, and abellcrank lever pivoted to a fixed point and connecting the said arm andvalve rod, substantially as described.

In testimony whereof I have hereunto set my hand this 19th1day ofNovember, 1890.

HENRY O. NICHOLS.

Witnesses:

ROBERT W. WATERBURY, WM. H. APPLETON.

